Fair Value Measurements (Level 3 Rollforward) (Details) - Southern California Edison - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Total realized/unrealized gains (losses):
Derivative liabilities reclassified to other liabilities		$ 914
Level 3
Fair Value Disclosures Level 3 [Roll Forward]
Fair value of net assets (liabilities) at beginning of period	$ 52	(1,012)	$ 101	$ (1,089)
Total realized/unrealized gains (losses):
Included in regulatory assets and liabilities	(21)	120	(70)	54
Contract amendment	0	0	0	143
Normal purchase and normal sale designation	0	914	0	914
Fair value of net assets (liabilities) at end of period	31	22	31	22
Change during the period in unrealized gains and losses related to assets and liabilities held at the end of the period	$ 7	$ 6	$ 7	$ 6

Derivative Liabilities Transfered Out Of Derivatives

No definition available.

Name:	eix_DerivativeLiabilitiesTransferedOutOfDerivatives
Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents total gains or losses for the period (realized and unrealized), included in regulatory assets and liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

No definition available.

+ Details

Name:	eix_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInRegulatoryAssetsAndLiabilities
Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss), Contract Amendment

+ References

No definition available.

+ Details

Name:	eix_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossContractAmendment
Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the change during the period in unrealized gains (losses) for financial instruments, held at the end of the period, with unobservable inputs (level 3).

+ References

No definition available.

+ Details

Name:	eix_IncreaseDecreaseDuringPeriodInUnrealizedGainsLossesRelatedToLevel3FinancialInstrumentsHeldAtPeriodEnd
Namespace Prefix:	eix_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

+ Details

Name:	eix_NetRealizedOrUnrealizedGainLossAbstract
Namespace Prefix:	eix_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19279-110258

+ Details

Name:	us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19279-110258

+ Details

Name:	us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=eix_SouthernCaliforniaEdisonCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: